Apparatus for crystallization.



No. 841,030. PATENTED JAN. 8, 1907. A. L. MARSHALL.

APPARATUS FOR ORYSTALLIZATION.

APPLICATION FILED MAR. 8, 1906 I an % PATENT ,T T TQE.

ALBERT L. MARSHALL, or NEW ORLEANS, LOUISIANA.

APPARATUS FOR cavsraruzarioa.

Patented Jan. 8, 1907.

To all whom it may concern.

Be it known that l, ALBERT L. MARSHALL,

' a citizen of the United States, residing at New Orleans, in the parish of Orleans and State of Louisiana, have invented certain newand useful Improvements in Apparatus for Crystallization in Motion; and I do hereby declare the followin to be a full, clear, and exact description. 0 the invention, such as will enable others skilled in the art to which it appertains to make and useg the same.

My invention relates to improvements in crystallizers, especially intended for the crystallization of sugar from the masse-cuite or syrup that has been boiled down to the desired degree of consistency; and it relates more especially to certain improvements on the crystallizer shown in my Patent No. 668,110, granted February 12, 1901.

It is well known that sugar may be crystallized out of syrup in two wayscither by allowing the syrup to stand quiescent for aconsiderable length of time, when the grains will form by a ser es of gradual accretions or by keeping the mass fromwhich the grains are separated in continual motion, when the grains increase in size more rapidly by mechanical action, which may be compared to the formation of hailstones or to the increasing size of a snowball rolling downhill.

. Where the 'masse-cuite is allowed to remain quiescent, it takes a much longer time to effeet the same amount of granulation than with the mechanical method, and in large factories where immense masses of. material are to be treated the cost of the granulating tanks or cars and storing same becomes a very important item. I

My present invention relates to the latter method of crystallization, where the granulation is accelerated by mechanical means, and the said invention will be understood by reference to the accompanying drawings, in which Figure 1 represents a central vertical section through the center of the improved crystallizer. Fig. 2 is a plan view showing the means for rotating the screw, and 3 is a detail showing the perforated annular air-pipe.

A represents a large tank, preferably cylindrical in form, provided with any suitable inlet A and any suitable outlet A The inlet and outlet pipes, valves, &c., are omitted, as being well known in the art. The tank is supported upon any suitable platform (not shown) in any convenient way. Throu h the center of the tank runs a vertical tube open at both ends and suitably sup orted, as

by means of the spider C and the races D.-

This tube supports a scattering-plate E, preferably in the form of 'alftruncated cone and braced by braces e. V

Journaled in the center of the tube B is a shaft F, carryin the screw G. This shaft is journaled at its ower end in the spider C and at its upper end in suitablei bearings H. This screw-shaft may be turned in any convenient way, as by means of the wormwheel F meshing with the w'ormjK on the shaft K, which shaft carries fast and loose pulleys K driven from 7 any} convenient source of power. In the bottom:0f the tube B an annular erforated pipe M is provided,-

which is supp ied with air from the pipe M. Hot or cold air may be fed to this pipe M from the pipes N and P, respectively, the sup ly being controlled bythe valvesn and p.

T e o eration of the device is as follows: The tan being charged with masse-cuite to the desired height-about the level as w-at the temperature from which it comes direct from the vacuum an, warm air is admitted to the pipe M, an passing through the perforations in the annular pipe M it carries the column of fluid in the tube B upward, at the same time agitatingthe same, and the col- 'umn overflows above the top of the tube and drains back over the scattering-plate E, where the action of the air is assisted byrotating the screw in the tube. The screw assists in lifting the mass and also in a measure in agitating the same, while the air-bubbles rising through the liquid in a constant direction produce such an agitation as will especially promote crystallization. By continuing the rotation of the screw and by gradually decreasing the temperature of the air-blast the granulation may be rapidly and efficiently accomplished.

it may be found in practice that by changing the temperature of the air fiom warm to cool and then back again to warm, or the reverse, the lowering of the temperature for the time being will start or facilitate granulation, and therefore it may be desirable to give certain variations of temperature to the inflowing air, especially at the beginning of the op.- eration. This treatment with air, however, would depend in a large measure upon the nature of the masse-cuitc being treated, as in IIC 

